Install psalm as dev, sync scripts updates

vendor/felixfbecker/language-server-protocol/src/DeclarationClientCapabilities.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace LanguageServerProtocol;
+
+class DeclarationClientCapabilities
+{
+
+    /**
+     * Whether declaration supports dynamic registration. If this is set to
+     * `true` the client supports the new `DeclarationRegistrationOptions`
+     * return value for the corresponding server capability as well.
+     *
+     * @var bool|null
+     */
+    public $dynamicRegistration;
+
+    /**
+     * The client supports additional metadata in the form of declaration links.
+     *
+     * @var bool|null
+     */
+    public $linkSupport;
+
+    public function __construct(
+        bool $dynamicRegistration = null,
+        bool $linkSupport = null
+    ) {
+        $this->dynamicRegistration = $dynamicRegistration;
+        $this->linkSupport = $linkSupport;
+    }
+}